Get the length of vectors (including lists) and factors,
and of any other object for which a method has been defined.
Usage
len(...)
Arguments
...
object
Value
For vectors (including lists) and factors the length is the number
of elements.
For an environment it is the number of objects in the environment,
and NULL has length 0.
For expressions and pairlists (including language objects and
dotlists) it is the length of the pairlist chain.
All other objects (including functions) have length one:
note that for functions this differs from S.
Details
len() cannot reset the length of a vector, while length() could.